Railway signaling system



H. s. YOUNG 2,205,555

RAILWAY SIGNALING SYSTEM Original Filed Aug. 30, 1934 2 Sheets-Sheet l 2/ B 0 aka a Rflbalb/ B Z A fig w my M 3 Di m I E Z T r a m 7% s H 9 fiww a. Y a S V. 1 5 I $59 3 Fi o m 3 M m g 9 f a o 69%;. 8 m #7 fi B b B b 5 4Z S 7 7 9 R 2 M, 67 m wn b. 5 w E ww a 5 w h I a 5 B 5 w 6 F5010 i m 7 fig I mm 8 0, a; A 1 5% A I 1 W a n 4 f 5 z a 1 w an bi 5 75 R w 3. W. 6 M2: m 9 w 5 2 GI W 1 W. w 9 9M. 1 T 5 Irv-Lb; 9r T E .r a, 1B a I Y a F L WQ W 0 wmm mAvfl mU 0 Z 0 5 r my .4 E

July 2, 1940.

His Qttorneg July 2, 1940. H. s. YOUNG 2,206,555

RAILWAY SIGNALING SYSTEM Original Filed Aug. 30, 1934 2 Sheets-Sheet 2 202 152 I56\ PQRB/LZP 152 ELJi mid? 51 153 [T5 B 162 5145 I l E 165 l 4 Juventor Henry 5.!u12g.

L z's attorney Patented July 2 1940 UNITED STATES 2,206,555 RAILWAY SIGNALING SYSTEM Henry S. Young, Wilkinsburg, Pa., assignor to The Union Switch-8t Signal Company, Swiss vale, Pa., a corporation of Pennsylvania "Original application August 30, 1934, Serial No.

742,095. Divided and this application December 14, 1938, Serial "No. 245,716

27 Claims;

My invention relates to railway signaling systems of the type involving light signals which are approach lighted.

One object of my invention is to provide means for checking the continuity of the lamp filament of a signal of the type described while the lamp is extinguished.

Another object of my invention is to provide a restrictive indication for trains approaching an approach lighted signal having a burned out lamp.

Other objects of my invention will appear as the description proceeds,

The present application is a division of my copending application Serial No. 742,095, filed August 30, 1934, for Railway signaling systems.

I shall describe several forms of signaling systems embodying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawings, Figs. 1 to 4; inclusive, are diagrammatic views showing'my invention applied to several different forms of signaling systems.

Similar reference characters refer to similar parts in each of the'several views.

Referring first to Fig. 1, the reference characters I and l designate the track rails of a stretch of railway track along which traffic normally moves in the direction indicated by the arrow. These track rails are divided, by means of insulated joints 2, to form blocks such as AB and B-C and each of these blocks is further subdivided to form track sections such as Aband 22-3. Although but two track sections are shown per block, it will be understood that more than two sections may be used, as determined by the length of the block, track conditions, and other factors. with a track circuit comprising a battery connected with the rails adjacent one end of the section and a neutral track relay connected with the rails adjacent the other end of the section, and

designated by the reference character TR. with a distinguishing exponent and subscript. Traffic entering each block is governed bya signal S having associated therewith an approach lighting relay designated by the reference character ALR with a distinguishing exponent, a distant relay designated by the reference character DR with a suitable distinguishing exponent, a battery designated by the reference character E with a distinguishing exponent, a power-01f relay designated by the reference character POR witha distinguishing, exponent, anda transformer desigposition, respectively. For convenience in illus- Each track section is provided nated by the reference character T with a distinguishing exponent. I

Located adjacent the entrance end of each block is a signal designated by the reference character S with an exponentcorresponding to 5 the location. Each 'signal,;as here shown, is of the type commonly known as a Searchlight sig-' nal, and comprises an armature 5 mounted to rotate between an intermediate position to which it is biased, and two extreme positions. Each armature 5 is controlled by an armature winding 6, and is polarized by the field from a permanent magnet or an electromagnet (not shown) in such a manner thatwhen the winding 6 is energized, the armature 5 will rotate'to its right-hand or left-hand extremeposition according as winding liis then supplied with current of normal or reversepolarity, respectively. Attached to each armature 5 to rotate therewith are three colored roundels G, R, and Y, whichare arranged'to be disposed in the path of a beam, of light projected from an associated lamp L according as the armature 5 occupies its right-hand extreme position, its intermediate position or its left-hand extreme tration, each lamp L in the drawing is shown disposed above the, associated roundels, but it will be readily understood that in actual practice each lamp will be located directly back of the asso ciated roundeland will have associated therewith a suitable optical system, not shown, for pro-' jecting a beam-of light [fromthe lamp. The signals S each indicate proceedff stop or "caution according asthe roundel G, R, or Y is infront of the associated lamp'llwhen this lamp is lighted. Operatively connected with each armature 5 is a circuit controller comprising two movable contact fingers? and 8. The movable contact finger i cooperates" with a fixed contact l to close a' contact "i'l= when the armature occupies its right-hand *extreme position, and with a fixed contact l to'close a contact l-'l when the armature occupies its intermediate position or its left-hand extremeposition; while the movable contact finger 8 cooperates with a fixed contact ti to close a contact 8- 8 when'the ar-' mature occupies its'left-handextreme position, and with a fixe'd'contact' 8 to close a contact 8-8 when the armature occupies'its intermediate or its right-hand extreme position. A signal of the type described is disclosed and claimed in Letters Patent of-the U nited StatesNo. 1,864,224; granted to Wesley B. Wells, on'June 21, 1932, for Light signals.- 7 Tl V p The Winding-B 'of-ea'ch' signal, as here shown,

TRt and TRi are both energized and distant relay DR-is alsoand contact 'l--l 'of signal S energized, and with a reverse energizing circuit which is closed when track relays TR? and TR} are both energized and distant relay DR. is deenergized. The normal energizing circuit for winding 6 of signal S passes from battery E through wires 5| and 52, winding of approach lighting relay ALR wire 53, front contact 54 of track relay 1 TRl wire 55, front contact 56 of track relay wire 51', front contact 5858 of distant relay DR wire 59, winding 6 of signal S wire 60, front contact Gl-SI of distant relay DR and Wire 62 back to batteryEB. The reverse energizing circuit for winding 6 is similar to the normal energizing circuit just traced with the exception that this latter circuit includes back contacts 58'---58 and (SF-Bi of distant relay DR. instead of front contacts 58-58 and '6I-'-6| of distant relay DR It follows that when block A-B i unoccupied so that track relays TRf, and TR? are both energized, signal S will occupy its proceed or caution position according as distant relay DR. is then energized or deenergized, respectively, and that when block A-B is occupied so that either track relay 'IR or TRi I is deenergized, signal S will occupy its stop position.

' It will be noted that both circuits for the winding 6 of each signal include the winding of the approach lighting relay ALR associated with the signal next in advance, and it follows therefore that each approach lighting relay will be energized or deenergized according as the block in the rear is unoccupied or is occupied.

Each distant relay DR is controlled by the signal next in advance and by the approach lighting relay ALB associated with said signal. Referring to relay DR for example, one circuit for this relay is closed when signal S indicates proceed and relay ALR. is energized. This circuit passes from battery E through wire 5|, front contact 6363 of relay ALR wire 64, the filament 'of lamp L wire 65, front contact 66$6 of relay ALR wire 61, contact 8-8 of signal S wire ll, contact 1- 'I of signal S wire 68, winding of relay DR, and wires 69 and 62 back to battery E Another circuit for relay DR. is closed when signal S occupies its caution position and relay ALR is energized. This latter circuit for relay DH is similar to the circuit just traced with the exception that this latter circuit includes contact 8 8 of signal S instead of contact 8-8 of signal S wire [1,

It will be apparent, therefore, that distant relay DR. will be energized when section A-B is unoccupied, signal S occupies its caution or proceed position, and filament of lamp L isintact.

Each power-off relay POR isconstantly connected with the secondary 41 of the associated transformer T, and the primary 46 of each transformer T is constantly connected with the terminals Z and O of a source of alternating current not shown in the drawings. It follows that each power-off relay will be energized at all times except in the event of an interruption in the alternating current supply.

Each signal lamp L is controlled by the associated approach lighting relay ALR and by the associated power-off relay POR. Referring particularly to lamp L for example, when relay ALR is deenergized, and relay POR. is energized, lamp L is supplied with alternating current over a circuit which may be traced from the left-hand terminal of transformer T through wires 16 and H, front contact 'I2'll of relay' POR wire 13, back contact 63--'63 of relay ALR wire 64, the filament of lamp L wire 65, back contact-66--66 of relay ALR wire 15, front contact 'l8'|8 of relay POR and wire 19 to the right-hand terminal of the secondary M of transformer T When, however, relay ALR. is deenergized and power-off relay POR is also deenergized, lamp L .is then supplied with direct current from battery E over a circuit which passes from battery E through back contact 12-12 of power-off relay POR wire 13, back contact 63 -63 of approach lighting relay ALR wire 64, the filament of lamp L wire 65, back contact 6666 of relay ALR wire 15, and back contact 'I8'l8 of relay POR to-battery E It follows that each signal lamp is extinguished except when the associated approach lighting relay isdeenergized.

In explaining the operation as a whole of the system. shown in Fig. 1, I shall assume that a train occupies section arA and that traffic conditions in advance are such that signals S and S both occupy their proceed positions. Under these conditions, track relay will be deenergized due to the train shunt, and approach lighting relay ALR will therefore also be deenergized, so that lamp L will be lighted. Signal S will accordingly display a proceed indication. Signal S however, will be dark.

When the train enters section Ab, track relay will become deenergized and will interrupt the circuitwhich was previously closed for winding 6 of signal S thus causing this signal to move to its stop position, and approach lighting relay ALR to become deenergized. The movement of signal S to its stop position will cause this signal to display a stop indication, since lamp L will then still be lighted, while the deenergization of approach lighting relay ALR will cause this latter relay to interrupt the circuit for distant relay DR and to complete one of the circuits for lamp L When the circuit for lamp L becomes completed, this lamp will become lighted, and since signal S occupies its proceed position, this signal will then display a proceed indication.

When the train has completely passed out of section a-A, track relay one of the circuits for-approach lighting-relay ALR will then become completed at front contact 54 of track relay will now be held open by the deenergization of track relay When the train has completely vacated section Ab, track relay will pick up, but the picking up of this relay will not have any immediate effect on the remainder of the apparatus for obvious reasons.

As the train progresses into section 3-0, the resultant deenergization of track relay will cause signal S to move to its stop position, and distant relay DR, to become deenergized in the same manner that the deenergization of track relay caused signal S to move to its stop position, and relay DR to become deenergized when the train entered section Ab. When signal S moves to its stop position, all circuits for distant relay DR. will be held open at the contacts controlled by this signal, and it follows that relay DR will remain deenergized as long as signal S remains in its stop position. When the train has passed completely out of section b--B, the resultant energization of track relay TRi will complete the reverse energizing circuit for winding 6 of signal S and this signal will then move to its caution position. Furthermore, since relay ALR. is included in the reverse energizing circuit for winding 6 of signal S when i this circuit becomes closed, relay ALR will pick up and will deenergize signal lamp L3, thus causing signal S to become dark. As the train progresses through the section to the right of section Bc no change in the apparatus will occur other than the picking up of track relay and the dropping of the track relay for the section occupied by the train. When the train passes out of the section to the right of section Bc, signal S will move to its caution position in the same manner that signal S moved to its caution position when the train'passed out of section bB, and when this happens the resultant closing of contact 88 of signal S will complete one of the circuits for distant relay DR thus causing this relay to become energized. When this relay becomes energized, it will interrupt the reverse energizing circuit for winding 6 of signal S and will completethe normal energizing circuit for winding 6 of this signal, and signal S will then move to its proceed position. As the train continues to proceed beyond the point B, distant relay DR. will finally pick up and cause signal S to move to its proceed position in a manner which will be obvious from the foregoing description. When signal S moves to its proceed position, all parts will be restored to the position in which they are illustrated in the drawings.

If, when the parts are in the position shown in Fig. 1, the filament of lamp L should become broken for any reason when the lamp is dark, the circuit for relay DR will then be interrupted at the filament of lamp L and as a result, relay DR will become deenergized, and will complete the reverse energizing circuit for winding 6 of signal S thus causing this signal to move to its caution position. It follows that with the apparatus constructed as shown in Fig. 1, if a signal lamp filament becomes broken when the lamp is dark, the signal next in the rear will move to its caution position, so that if a train approaches this signal, a caution indication will be displayed thereby. It will be seen, therefore, that with the apparatus constructed as shown in Fig. 1, the distant relays DR serve to check the continuity of the filament of the lamp for the signal next in advance while this lamp is dark.

Referring next to Fig. 2, as here illustrated, the rails I and I of the stretch of track shown in the drawing are divided into blocks such as A-B in the same manner as in the preceding view, and each block is provided with a track circuit including a battery 56 connected with the rails at the exit end of the section, and a neutral track relay, designated by the reference character TR with a suitable distinguishing exponent, connected with the rails at the entrance end of the section. Trafilc entering each block is governed by a signal S, which signal as here shown has associated therewith an approach lighting relay designated by the reference character ALR. with a distinguishing exponent, a distant relay designated by the reference character DR with a distinguishing exponent, a light-out relay designated by the reference character LOR with a distinguishing exponent, a power-off relay designated by the reference character POR. with a distinguishing exponent, a battery designated by the reference character E with a distinguishing exponent, and a transformer designated by the reference character T with a distinguishing exponent.

Each approach lighting relay, as here shown, is made suiiiciently slow releasing so that its front contacts will remain closed during the interval of time required for the associated signal to move from its caution to its proceed position or vice versa.

The winding 6 of each signal S is controlled by the associated track relay TR and the associated distant relay DR. Referring particularly to Winding 6 of signal S this winding is provided with a normal energizing circuit which passes from battery E through wires 80, 8!, 82 and 83,.front contact 851 of track relay TR wire 85, front contact 86-66 of distant relay DR wire B'l, winding 6 of signal S wire 88, front contact Bil-439 of relay DR and wires 96 and Si back to battery E This circuitis closed when and only when track relay TR and distant relay DR,

are both energized, and when this circuit is closed, winding 6 of signal S is supplied with current of normal polarity, with the result that this signal then occupies its proceed position.

Winding B of signal S is also provided with a reverse energizing circuit which is similar to the normal energizing circuit just traced with the exception that this latter circuit includes back contacts tit-86 and 233-439 of distant relay DR. instead of front contacts 8686 and BEL-89 of relay DR This latter circuit is closed when and only when track relay TR is energized and distant relay DE is deenergized, and when this circuit is closed winding 6 is supplied with current of reverse polarity, thus causing signal S to occupy its caution position. When track relay TR is deenergized, both the normal and reverse energizing circuits for signal S are then open, and under these conditions signal S occupies its stop position.

Each distant relay is controlled by the associated track relay TR. and by the circuit controller of the signal next in advance, as well as by the approach lighting and light-out relays associated with the signal next in advance. Referring particularly to relay DR this relay is provided with a pickup circuit which passes from battery E through wires 8E3, 8|, and 92, front contact $3 of light-out relay LOR wires 94 and 95, contact $8 of signal S wire 96, winding of relay ALR wire 9?, front contact 98 of track relay TR wire 99, winding of relay DR and wire it back to battery E Relay DH is also provided with two holding circuits one of which is closed when track relay TR. and approach lighting relay ALR are both energized, and signal S occupies its proceed position, and the other of which is closed when track relay TR and approach lighting relay ALR are both energized and signal S occupies its caution position. The holding circuit which is closed when signal S occupies its proceed position passes from battery E through wires 80, 8|, 92 and lnl, the filament of lamp L wire "32, front contact lii3-i63 of relay ALR wire 95, contact 8-8 of signal S wire l1, contact 'l---'l of signal S wire 98, winding of relay ALR wire 97, front contact 85 of track relay TR wire 95, winding of relay DE and wire Hi9 back to battery E The holding circuit for relay DR whichis closed when signal S occupies its caution position is similar to the circuit just traced with the exception that this latter circuit includes contact 8 3 of signal S in place of contact 8--8 of signal S wire I? and contact 1-? of signal S Each power-off relay POR is controlled in the manner described in connection with Fig. 1, and this control will be apparent from the drawings without further description.

Each lamp L is provided with a normal energizing circuit which is closed when the associated' power-off relay is energized and the associated approach lighting relay ALR is deenergized, and with an auxiliary energizing circuit which is closed when the associated power-off and light-out relays are both deenergized. Referring particularly to lamp L the normal energizing circuit for this lamp may be traced from the left-hand terminal of the secondary 40 of transformer T through wire I04, front contact 105, the winding of relay LOR wire [01, back contact SSS-i83 of relay ALB wire I02, the filament of lamp L and wires IUI, S2 and 82, to the right-hand terminal of secondary 4c of transformer T The auxiliary energizing circuit for lamp L passes from battery E through wires 80, 8|, 92-and H, the filament of lamp lfl--ll35 of power-off relay POR wire L wire I02, back contact lll3---lll3 of relay ALR wire I01, the winding of relay LOR wire [06, back contact I 05-405 of power-off relay POR and wire 9| to battery E.

It will be apparent that both circuits for the lamp include the winding of the light-out relay LOR and that when theone circuit is closed, the lamp is supplied with alternating current, whereas when the other circuit is closed the lamp issupplied with direct current. It is desirable that each relay LOR should pick up when either circuit for the associated lamp is closed, and each of these relays is accordingly so constructed that it will operate on either alternating or direct current.

It will also be apparent that the pickup circuit for relay DR for example, is completed at front contact 93 of relay LOR whereas both holding circuits for relay DR. are completed at front contact lll3--lll3 of approach lighting relay ALR It will further be noted that relay LOR only becomes energized when relay ALR becomes deen'ergized, and since relay ALR is included in both circuits for relay DR it follows that it is desirable that relay LOR should hold its front contact closed when the pickup circuit for relay DR, becomes completed until after relay ALR has picked up its armature and closed the holding circuit for this relay. To render relay LOR sufficiently slow in releasing to accomplish this desirable result, a rectifier H is shunted across the winding of relay LOR Each of the other light-out relays has a rectifier shunted across the winding of the relay for a similar purpose.

As shown in Fig. 2, all parts are in their normal position. That is to say, all relays but the two light-out relays are energized, signals SA and S both occupy their proceed position and lamps L and L are both extinguished.

When a train enters the block to the left of block AB, approach lighting relay Allllt will become deenergized due to the deenergization of the track relay TR for this block, and when relay ALB becomes deenergized, one or the other of the circuits for lamp L will become closed according as power-off relay PO Et is then energized or deenergized. I The closing of one of the circuits for lamp L will cause this lamp to become lighted, and since signal S occupies its proceed position, this signal will then displaya proceed indication. The closing of one of the circuits for lamp L will also cause relay LOR. to pick up, but the picking up of this relay will have no immediate effect on the remainder of the apparatus.

7 When the train enters block A-B, track relay TR will become deenergizecl and will interrupt all circuits for winding 6 of signal S thus causing this signal to move to its stop position. When this happens, the circuit for relay ALR will become open at the contacts controlled by signal S and relay ALR will, therefore, remain deenergized even after the train has vacated the block to the left of block A-B and permitted the track relay for this block to pick up. The deenergization of track relay TB in addition to causing signal S to move to its stop position, will interrupt the circuit for relay DR and this relay and approach lighting relay ALR will therefore both become deenergized. The deenergization of relay DR will have no immediate effect on the remainder of the apparatus, but the deenergization of approach lighting relay ALR will cause lamp L to become lighted,

and light-out relay LOR to become energized.

When lamp L becomes lighted, signal S will display a proceed indication.

.When the train enters the block to the right of block AB, track relay TR will become deenergized and will cause signal S to move to its stop position and distant relay DR to become deenergized. When signal S moves to its stop position, all circuits for relay DR will then be open at the contacts controlled by this signal and relays DR and ALB, will, therefore, remain deenergized as long as signal S remains in its stop position. When track relay TR picks up due to the train having completely passed out of block AB, the reverse energizing circuit for winding 6 of signal S will become closed, and signal S will then move to its caution position. The movement of signal S to its caution position will complete one of the circuits in which relay ALR is included, and this relay will then pick up and will interrupt the circuit for lamp L thus causing this lamp to become extinguished, and light-out relay LOR. to become deenergized.

When the train leaves the block to the right of block AB, track relay 'IR will pick up but relay DR, will remain deenergized. Signal S will therefore move to its caution position so that it will then display a caution indication. The movement of signal S to its caution position will complete the pickup circuit for relay DR and this relay and relay ALR will then both pick up. When relay DR. picks up, it will complete the normal energizing circuit for winding 6 of signal S and signal S will then move to its proceed position. The picking up of relay ALR will interrupt the circuit for lamp L and this lamp will then become extinguished and light-out relay LOR will become deenergized. The deenergization of relay LOR will tend to interrupt the pickup circuit for relay DR but due to the presence of rectifier I-I across the front contacts lil3ll'l3 of relay ALR, becomes closed, one of the holding circuits for relay DR will then be closed, with the result that relays DR and ALR. will both remain continuously energized under these conditions. When the train has proceeded far enough in advance of block AB, relay DR will pickup and will complete the normal energizing circuit for signal S thus causing this signal to move to its proceed position.

If, with the parts in the position shown in Fig. 2, the filament of lamp L for example, should become broken for any reason when the lamp is extinguished, the circuit which was previously closed for relay DR will become interrupted, and relay DR will then become deenergized, and will reverse the polarity of the current supplied to winding 6 of signal S so that this signal will move to its caution position. As a result, when a train subsequently enters the block to the left of block AB, and causes lamp M to become lighted, signal S will display a caution instead of a proceed indication, thus eliminating the undesirable condition of having an engineman pass signal S when this signal is displaying a proceed indication and finding the signal S dark.

It will be apparent, therefore, that with a signaling system constructed as shown in Fig. 2, the burning out of a signal lamp when the signal in the rear thereof occupies its proceed position will cause the signal in the rear to immediately move to its caution position.

Referring now to Fig. 3, the track circuits and signals shown in this view are the same as in Fig. l, but in Fig. 3 the winding 6 of each signal is controlled by the two track relays TR for the associated block and by the auxiliary relay associated with the signal'next in advance, through the medium of a polarized line circuit which in-' cludes the winding of the approach lighting relay for the signal next in advance. Referring to signal S for example, when track relays TR; and TRi are both energized and relay AR is also energized, the polarized line circuit for winding 6 of signal S is closed and, under these conditions, I

line wire H6, front contact I ll of track relay wire H8, winding 6 of signal S wire H9, front contact I20 of track relay TR? line wire l2l, front contact I22 of track relay wire I23, front contact I24-l24 of relay AR and Wire I25 back to battery E When track re-. lays TR; and TR are both energized and auxiliary relay AR is deenergized, the polarized line circuit for winding 6 of signal S is again closed but, under these conditions, due to the fact that the pole-changing contacts of relay AR are now reversed, winding 6 is supplied with current of reverse polarity over this circuit.

It should be pointed outthat since the approach lighting relay associated with each signal is included in the circuit for the winding 6 of the signal in the rear, and since this circuit includes front contacts of the two track relays for the two track sections next in rear of the asso ciated signal, the approach lighting relay for each signal will be energized except when the block in the rear of such signal is occupied by a train.

For reasons which will be apparent from an inspection of the drawings, it is desirable that each approach lighting relay should hold its front contacts closed during the interval of time between the opening of the back contacts and the closing of the front contacts of the associated auxiliary relay AR, and to accomplish this result, each approach lighting relay has a rectifier designated by the reference character H with a suitable distinguishing exponent shunted across its winding.

Each auxiliary relay is controlled by the circuit controller of the associated signal, by the track relay for the first track section in advance of the associated signal, and by the associated approach lighting relay. Referring particularly to relay AR for example, this relay is provided with one circuit which is closed when track relay and approach lighting relay ALE. are both ener-v gized and signal S occupies its proceed position, this circuit passing from battery E through wires III] and I26, the filament of lamp L wire I27, front contact I28I2B of relay ALR wire I29, front Contact 9 of track relay wire I6, contact 8-8 of signal S wire I'I, contact 'I*I of signal S wire l3il, the winding of relay AB and wires IN and I25 back to battery E Relay AR is also provided with another circuit which is closed when track relay and relay ALB, are both energized and signal S occupies its caution position, that latter circuit being similar to the circuit just traced with the exception that this circuit includes contact 88 of signal S in place of contact 8-43 of signal S wire El, and contact 'I'I of signal S It will be noted that both circuits for each auxiliary relay include the filament of the lamp of the associated signal, and it follows that if the filament of this lamp becomes broken, when either of these circuits is closed, the associated auxiliary relay will become deenergized. The resistance of each auxiliary relay is such that when either circuit for this relay is closed, the associated lamp will remain extinguished.

Associated with each signal are a power-off relay PCB and a transformer T connected and arranged in the manner previously described in connection with Fig. l.

Each signal lamp L is controlled by the associated approach lighting relay ALR and by the associated power-01f relay POE. Referring particularly to lamp L when relay ALB is deenergized and relay POR is energized, lamp L is then energized by alternating current over a circuit which may be traced from the left-hand terminal of secondary ii! of transformer T through wires I32 and I33, front contact I34I34 of power-off relay POR wire I35, back contact I28I28 of relay ALR wire 527, the filament of lamp L and wires I26, H8, I36 and I31 to the right-hand terminal of secondary 40 of transformer T When, however, relay ALR, is deenergized, and power-off relay POR is also deenergized, lamp L is then energized by direct current over a circuit which may be traced from battery E through wires Hi3 and $26, the filament of lamp L wire I27, back contact Ii!8I28 of relay ALR wire 535, back contact I34--Ii-li of power-off relay POR and wire 538 back to battery E In explaining the operation as a whole of the apparatus shown in Fig. 3, I shall assume that section aA is occupied by a train, and that trafiic conditions in advance are such that signals S and S both occupy their proceed positions. With section aA occupied, track relay will be deenergized and the circuit for approach lighting relay ALR will therefore be interrupted at the front contacts H5 and I22 of track relay S occupies its proceed position, this signal will display a'proceed indication.

When the train enters section A-b, track relay will become deenergized and will interrupt all circuits for winding 6 of signal S thus causing this signal to move to its stop position, and approach lighting relay ALR to become deenergized. The deenergization of approach lighting relay ALR will interrupt the circuit which was previously closed for auxiliary relay AR and this relay will now also become deenergized. The deenergization of this relay, however, under these conditions, will have no immediate effect on the remainder of the apparatus. The deenergization of approach lighting relay ALR will also cause one of the circuits for lamp L to become completed, and this lamp will therefore become lighted, thus causing signal S to display a proceed indication. When: the train passes completely out of section aA, track relay will pick up, and when this relay picks up under these conditions, one of the circuits for the winding 6 of the signal for the associated block will become completed which will cause relay ALR to become energized. When the train enters section b-B, track relay will become deenergized but since all circuits controlled by this relay were previously opened at contacts Ill and I20 of track relay TR; the deenergization of relay will have no immediate effect on the remainder of the apparatus. When the train has passed completely out of section Ab, track relay TR; will pick up, but the picking up of this relay will also have no immediate effect on the remainder of the apparatus.

When the train enters section B-c, track relay will become deenergized and will deenergize winding 6 of signal S thus causing this signal to move to its stop position. When the train has vacated section b--B, track relay will pick up, and will complete the reverse energizing circuit for winding 6 of signal S thus causing this signal to move to its caution position, and approach lighting relay ALR to pick up. When the signal reaches its caution position, the resultant closing of contact 88 of this signal will complete one of the circuits for relay AR thus causing this relay to become energized. When this occurs, the circuit for relay ALR will be momentarily interrupted, but due to therectifier H this relay will not open its front contact I28-I28 under these conditions. The picking up of approach lighting relay ALR. will interrupt the circuit for lamp L which was previously closed at back contact I28 I28 of relay ALB, and lamp L will become extinguished. When the train leaves section Bc, track relay will pick up, but this will not have any effect on the remainder of the apparatus until after the train has passed completely out of the block to the right of point B, at which time signal S will become energized in its reverse direction, and will move to its caution position in the same manner that signal S became energized in its reverse direction and moved to its caution position when the train passed out of block AB. When signal S moves to its caution position, one of the circuits for relay AR will become completed, and this relay will then pick up and will reverse the polarity of the current supplied to winding 6 of signal S thus causing this sig- I nal to move to its proceed position. When the train has passed completely out of the second block in advance of block AB, winding 6 of signal S will become energized in its normal direction and signal S will then move to its proceed position. When signal S reaches its proceed position, all parts will then be restored to the position in which they are shown in the drawings.

I shall now assume that with the parts in the position shown in Fig. 3, the filament of lamp L becomes interrupted. Under these conditions, the circuit which was previously closed for relay AR will be interrupted at the lamp filament and relay AR will, therefore, become deenergized, and will reverse the polarity of the current supplied to winding 6 of signal S thus causing this signal to move from its proceed to its caution position. As a result, if a train subsequently approaches signal S this signal will display a caution indication instead of a proceed indication, and the engineman will, therefore, be prepared to stop when he reaches signal S Referring now to Fig. 4, as here shown, the track circuits and signals. are the same as in Fig. 3, but in Fig. 4, each signal has associated therewith, in addition to the apparatus shown in Fig. 3, a light-out relay designated by the reference character LOR with a suitable distinguishing exponent. Fig. 4, the circuits are so arranged that each signal is lighted as long as the associated block is occupied.

Referring to signal S for example, one circuit for winding 6 of this signal is closed when track relays TR? and TR} are both energized, and relay AR is energized, and this circuit passes from battery E through Wires I45, I63, I64 and I46, the winding of relay ALR wire I41, front contact Mil-I48 of relay AR wire I49, front contact I50 of track relay TR} line wire I5I, front contact I52 of track relay TR? wire I53, winding 6 of signal S wire I54, front contact I55 of track relay wire I56, front contact I51 of track relay TRi wire I58, front contact I'.i9---I59 of relay AR and wires I60, I6! and I62 back to battery E When this circuit is closed, winding 6 of signal S is supplied with current of normal polarity and, under these conditions, signal S will cupy its proceed position. Another circuit for winding 6 of signal S is closed when track relays TR? and TRi are both energized, and relay AR is deenergized,

Furthermore, as shown in and passes from battery E through wires I45, I63, I64.and I 46, a resistance R back contact I 59I 59 of relay AR wire I58, front contact I51 of track relay TR? wire I56, front contact I55 of track relay TR; wire I54, winding 6 of signal S wire I53, front contact I52 of track relay line wire II, front contact I50 of track relay wire I49, back contact I48--I48 of relay AR and wires I60, I6I and I62 back to battery E When this latter circuit is closed, the winding 6 of signal S is supplied with current of reverse polarity, and, under these conditions, signal S occupies its caution position.

It will be noted that approach lighting relay ALR is included in the circuit first traced for winding 6 of signal S and it follows that this relay will be energized whenever signal S occupies its proceed position. It will also be noted that the other circuit for winding 6 of signal S does not include the winding of relay ALRB, but does includes resistor RF The resistance of the resistor R is the same as that of the Winding of relay ALR and the function of this resistor is to maintain the resistance of both circuits for winding 6 of signal S at the same value, so that when either one of these circuits is closed, winding 6 will be supplied with current of the same magnitude.

Each auxiliary relay AR. is provided with two circuits which are controlled by the associated signal S and by the associated light-out relay LOR, and with two other circuits which are controlled by the associated signal S and. by the associated approach lighting relay ALR. Referring to relay AR for example, one circuit for this relay is closed when the signal S occupies its proceed position and light-out relay LO'R is energized, and may be traced from battery E through wires I45, I63 and I64, front contact I65 of relay LOR wires I66 and I61, contact 6-8 of signal S wire I1, contact 1-1 of signal S wire I68, winding of relay AR and wires I69, I 6| and I62 back to battery E Another circuit for relay AR. is closed when signal S occupies its caution position and relay LOR is energized, and is similar to the circuit just traced with the exception that this latter circuit includes contact 3-43 of signal S in place of contact 8-6 of signal S wire I1 and contact 'I---1 of signal S A third circuit for this relay is closed when signal Se occupies its proceed position and relay ALR, is energized, and passes from battery E through wires I45, I63, I64, I46 and Ill, the filament of lamp L Wire I12, front contact His-I13 of relay ALR wire I61, contact 86 of signal S wire I1, contact 'I-l of signal S Wire I68, winding of relay AP, and wires I66, I6I and I62 back to battery E A fourth circuit for relay AR. is closed when signal S occupies its caution position and relay ALR is energized, and is similar to the circuit just traced ciated power-off relay. Referring particularly to lamp L for example, when approach lighting relay ALR is deenergized and power-ofi relay PO'R is energized, lamp L is lighted by virtue of an energizing circuit which may be traced from the right-hand terminal of transformer T through wires I63, I64, I46 and I'll, the filament of lamp L wire I12, back contact I'I3---I'l3 of relay ALB wire I15, winding of relay LOR wire I16, front contact Il"!ITI of power-off relay POR and wires I13 and I19 to the lefthand terminal of secondary winding 40 of transformer T When, however, approach lighting relay ALR. is deenergized and power-off relay POR is also deenergized, lamp L is then lighted by virtue of another energizing circuit which may be traced from battery E through wires I45, H33, I64, M6 and IN, the filament of lamp L wire I12, back contact H3Il'3 of approach lighting relay ALR wire I15, winding of lightout relay LOR wire I16, back contact I'll-J11" of power-off relay POR and wire I62 back to battery E It will be noted that the light-out relay LOR, is included in both energizing circuits for lamp L and that one of these circuits is energized by alternating current, whereas the other circuit is energized by direct current. Relay LOR, is designed to operate on either alternating 01' direct current, and the parts of the relay are so proportioned that when either one of the energizing circuits for lamp L is closed, this relay will pick up its armature and close its front contact.

In explaining the operation as a whole of the system shown in Fig. 4, I will assume that a train occupies section aA, and that traffic conditions in advance are such that signals S and S both occupy their proceed positions. Under these conditions, track relay will be deenergized due to the train shunt, and approach lighting relay ALR will therefore also be deenergized, so that lamp L will be lighted and light-out relay LOR. will be energized. Signal S will therefore display a proceed indication. Furthermore, relay AR will be held energized by virtue of the circuit for this relay including front contact I65 of lightout relay LOR When the train enters section; A--b, track relay will become deenergized and will interrupt both circuits for winding 6 of signal S thus causing this signal to move to its stop position, and causing approach lighting relay ALR and relay AR to become deenergized. The movement of signal S to its stop position will cause this signal to display a stop indication, since lamp L is then lighted; while the deenergization of approach lighting relay ALR. will interrupt the circuit which was previously closed for relay AR and will complete one of the circuits for lamp L When the circuit for lamp L becomes completed, this lamp will become lighted, thus causing signal S to display a proceed indication. Furthermore, relay LOR will pick up and will complete another circuit for relay AR thus causing this relay to remain energized. It should be pointed out that relay AR is sufliciently slow releasing so that it will not open its front contacts between the opening of the one circuit for this relay at front contact I'I3I'I3 of relay ALRF and the closing of the other circuit for this relay at front contact I65 of relay LOR 'When the train haspassed completely out of section a-A, track relay will pick up, but approach lighting relay ALR will remain deenergized since the circuit in which this relay is included will then still be open at front contact I48I48 and I5!lI59 of relay AR It will be seen, therefore, that lamp L will remain lighted, thus causing signal S to continue to display a stop indication, even though the train: is now past this signal.

When the train enters section b-B, track relay will become deenergized, but no change will ocour in the indication of signal S since the circuits for this signal which were previously opened by the deenergization of track relay TRa are now held open by the deenergization of track relay When the train has vacated section Ab, track relay will pick up, but the picking up of this relay will have no immediate effect on the apparatus for obvious reasons.

As the train progresses into section B-c, the resultant deenergization of track relay will cause signal S to move to its stop position, and when this happens, relay AR willbecome deenergized and will open the circuit for winding 6 of signal S including the winding of approach lighting relay ALR at front contacts I48I48 and I5!l-I.'i9 of this relay. When the train has vacated section b-B, track relay will pick up and will complete the reverse energizing circuit for winding 6 of signal S thus causing this signal to move to its caution position. When signal S moves to its caution position, the circuit for auxiliary relay AR, including contact 88= of signal S and front contact I65 of light-out relay LOR will become completed, and relay AR will therefore pick up. When this occurs, the circuit in which approach lighting relay ALR is included will become com pleted and relay ALR. will then pick up, thus interrupting the circuit which was previously closed for lamp L and hence causing light-out relay LOR to become deenergized.

As the train continues to proceed beyond signal S no further change in the apparatus will take place until the train has passed completely out of the block to the right of block AB, at which time winding 6 of signal S will become energized in the reverse direction, and will cause signal S to move to its caution position. When signal S reaches its caution position, relay AR will become energized in the same manner that relay AR, became energized when signal S moved to its caution position; and the energization of relay AR in turn, will complete the normal energizing circuit for winding 6 of signal S thus causing signal S to move to its proceed position, and. approach lighting relay ALR. to become energized. When signal S moves from its caution position to its proceed position, the circuit for relay AR which was previously closed at front contact 88 of signal S will become interrupted and another circuit for this relay will become closed at contacts 8--8 and 1-4 of signal S Relay AR however, is sufficiently slow releasing so that it will not open its front contacts under this condition. The energization of approach lighting relay ALR will interrupt the circuit which was previously closed for lamp L thus causing lamp L to become extinguished and light-out relay LOR to become deenergized. When light-out relay LOR becomes deenergized,

the circuit for relay AR which was previously closed at front contact 65 of this relay will become interrupted, but relay AR will remain energized because another circuit for this relay will then be closed at front contact lie-H3 of approach lighting relay ALR As the train continues to progress beyond the signal S winding 6 of this signal will finally become energized in the normal direction and cause signal S to move to its proceed position. As the signal moves to this position, the circuit which was previously closed for relay AR at contact 8-.8 of signal S will become interrupted and another circuit for this relay will become closed at contacts 3-45 and l-l of signal S Relay AR however, maintains its front contacts closed, under this condition, due to its slow releasing characteristic. With signal S restored to its proceed position, all parts are restored to the position in which they are shown in the drawings.

If, with the apparatus constructed as shown in Fig. 4, the filament of lamp L should become broken or interrupted for any reason while the lamp is extinguished, the circuit for relay AR will become interrupted at the filament of the lamp, and this relay will therefore open its front contacts and close its back contacts, thus reversing the polarity of the current supplied to winding 6 of signal S and hence causing this signal to move to its caution position. A similar operation will occur if the filament of the lamp associated with any of the other signals becomes broken under like conditions.

Although I have herein shown and described only a few forms of signal systems embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a stretch of railway track divided into blocks, each of said blocks being further divided toform a plurality of track sections; a track circuit for each track section including a track relay, a light signal for governing trafiic entering into each block including an electric lamp and a signal mechanism movable to a stop, proceed, or caution position according as said mechanism is deenergized, energized with current of normal polarity, orenergized with current of reverse polarity; an approach lighting relay, a slow releasing distant relay, and a source of direct current associated with each signal; a circuit for each signal mechanism including polechanging contacts on the associated distant relay, front contacts of the track relays for the track sections of the block next in advance of the signal, the winding of the approach lighting relay for the signal next in advance, and the source of direct current associated with the signal next in advance; a circuit for each distant relay including the filament of the lamp for the signal next in advance and the source of direct current associated with the signal next in advance and closed only when the signal next in advance occupies its caution or proceed position and the approach lighting relay associated with the signal next in advance is energized, and means for energizing each signal lamp when the associated approach lighting relay is deenergized.

2. In combination, a stretch of railway track divided into blocks, a track circuit for each block including a track relay, a signal for governing the entrance of traffic into each block including an electric lamp and a signal mechanism provided with a winding, each said signal mechanism being movable to a stop, proceed or caution position according as the associated winding is deenergized or is energized with current of normal or reverse polarity, a slow releasing approach lighting relay, a light-out relay, and a slow releasing distant relay associated with each signal, a circuit for the winding of each signal mechanism including pole-changing contacts on the associated distant relay, and a front contact of the track relay for the associated block; a holding circuit for each distant relay including a front contact of the associated track relay, the winding of .the approach lighting relay associated with the signal next in advance, contacts controlled by the signal mechanism of the signal next in advance, a front contact of the approach lighting relay associated with the signal next in advance, and the filament ofthe lamp for the signal next in advance; a pickup circuit for each distant relay including a front contact of the associated track relay, the winding of the ap proach lighting relay associated with the signal next in advance, contacts controlled by the signal mechanism for the signal next in advance,

and a front contact of the light-out relay associated with the signal next in advance, and a circuit for each lamp including a back contact of the associated approach lighting relay and the Winding of the associated light-out relay, a

rectifier being shunted across the winding of track circuit for each track section including a track relay, a light signal for governing the entrance of trafiic into each block including an electric lamp and a signal mechanism movable,

to a stop, proceed, or caution position according as said mechanism is deenergized, energized with current of normal polarity, or energized with current of reverse polarity; an approach lighting relay and a slow releasing relay associated with each signal, a circuit for each signal mechanism including front contacts of the track relays for the track sections of the block next in advance, pole-changing contacts on the slow releasing relay associated with the signal-next in advance, and the winding of the approach lighting relay associated with the signal next in advance; a rectifier shunted across the winding of each approach lighting relay to make it slow releasing; a

circuit for each slow releasing relay including contacts controlled byv the associated signal mechanism, a front contact of the track relay for the track section next in advance of the associated signal mechanism, a front contact of the associated approach lighting relay, and the filament of the lamp of the associated signal; and means for energizing each signal lamp when the associated approach lighting relay is deenergized.

4. In combination, a stretch of railway track divided into blocks, eachsaid block being further divided to form a plurality of track sections, a track circuit for each track section including a track relay, a light signal for governing the entrance of traffic into each block including an electric lamp and a signal mechanism movable to a stop, proceed, or caution position according as said mechanism is deenergized, energized with current of normal polarity, o-r energized with current of reverse polarity; a slow releasing rel an approach lighting relay, a resistor, and a lightout relay associated with each signal, each said resistor having substantially the same resistance as the associated approach lighting relay; a normal energizing circuit for each signal mechanism including front contacts of the track relays for the track sections of the block next in advance, afront contact of the slow releasing relay ass-e ciated with the signal next in advance and the winding of the approach lighting relay associated with the signal next in advance; a reverse energizing circuit for each signal mechanism including front contacts of the track relays for the track sections of the block next in advance, a back: contact of the slow releasing relay asscciated with the signal next in advance, and the resistor associated with the signal next in advance; a circuit for each slow releasing relay including contacts controlled by the associated signal mechanism, a front contact of the associated approach lighting relay, and the filament oi the associated lamp; another circuit for each slow releasing relay controlled by the associated signal mechanism and by a front contact of the associated light-out relay, and means for connecting each lamp in series with the associated light-out relay and a source of current when the associated approach lighting relay is deenergized.

5. In a railway signaling system, spaced sig nals each having an incandescent lamp, a track. circuit associated with each of said signals, polarized line circuit for controlling the indica= tion displayed by each signal, a constantly en-- ergized relay at each signal connected in series with the incandescent lamp, automatic means for each signal governed by the associated track circuit for controlling each line circuit in accord-- ance with forward traffic conditions, and means for controlling each line circuit to effect the dis' play of a restrictive indication at the associated signal by the deenergization-oi the relay at the forward signal.

6. In a railway signaling system, spaced signals each having an incandescent lamp, a track circuit associated with each of said signals, a control line circuit for each signal normally energized with one direction of current for effecting the display of a clear signal indication, automatic means for each signal governed by the associated track circuit for reversing the direction of current in the line circuit for effecting the display of a caution indication in accordance with forward traific conditions, a constantly energized relay for each signal responsive to the flow of current through the associated incandescent lamp, and means for reversing the direction of current in the line circuits by operation acoasss of the relays, whereby to display a caution indication at a rear signal upon the failure of an incandescent lamp.

'7. In a railway signaling system, a track divided into blocks, a track circuit for each block, a wayside signal including an incandescent lamp associated with each block, a line circuit for each block extending between associated signal of ad jacent blocks for controlling the signals, a constantly energized relay for each signal responsive to the flow of current through the associated incandescent lamp, and means for controlling each line circuit by the associated relay and the assoelated track circuit.

8. In combination, a first and a second section of railway track, a track circuit for said second section, an approach energized light signal for each section for governing traffic entering therein,a line circuit for said second section, and means governed by said track circuit as well as said line circuit and rendered eifective upon a failure of the light source of the signal for said first section for causing the signal for said second section to display a more restrictive indication at such time as a train approaches the signal for said second section and said two sections are both unoccupied.

9. In combination, a track circuit for said secand section, a first and a second section of railvay track, a first and a second approach lighted signal for governing traflic entering said first and said second sections respectively, a line circuit for said second section, and means governed by said track circuit and said line circuit and efiective when said first signal becomesincapable of providing an indication for causing said second signal to display a more restrictive indication when a train approaches said second signal and said two sections are both unoccupied.

10. In combination, a stretch of railway track divided into blocks, a track circuit for each block, a signal for each block for governing the entrance of traific into the associated block and including a lamp, a lighting circuit for each lamp efiective when a train enters the block next in the rear to cause the associated signal to display an indication, and a line circuit governed by said track circuit and by said lamp when unlighted and efiective upon failure of the lamp filament for controlling the signal for said rear block.

11. In combination, a stretch of railway track divided into blocks, a signal for governing the entrance of traific into each block and including a lamp, a lighting circuit for said lamp effective when a train enters the block next in the rear to cause the signal to display an indication, a normally closed line circuit including the filament of said lamp but ineffective to cause the lamp to become lighted, and normally energized means included in said line circuit for controlling the signal for said rear block.

L1 combination, a stretch of railway track divided into blocks, a signal for governing the entrance of trafiic into each block and including a lamp, a lighting circuit for said lamp efiective when a train enters the block next in the rear to cause the signal to display an indication, a normally energized checking relay for each signal governed by the lamp filament of the signal associated therewith at such time as said lamp is not lighted but said filament is intact, and a line circuit for controlling each signal,

relay for the signal next in advance.

13. In combination, a stretch of railway track divided into blocks, a signal for governing the entrance of trafilc into each block and including a normally unlighted lamp, a lighting circuit for said lamp effective when a train enters the block next in the rear to cause the signal to display an indication, a checking circuit for each signal for checking the integrity of the lamp filament of said unlighted signal associated therewith, and a line circuit for controlling each signal, said line circuit being governed by the checking circuit for the signal next in advance.

14. In combination, a stretch of railway track divided into blocks, a track circuit for each block, a signal including a single light source comprising an incandescent filament for governing the entrance of trafiic into each block, and means for each block and including a normally energized line circuit governed by the associated track circuit for controlling each signal, said means being controlled by the filament of the lamp for the signal next in advance and effective whenever such filament becomes broken to cause the signal in the rear to display a restrictive indication for an approaching train.

15. In combination, a first and a second section of railway track, a track circuit for each section, a light signal for each section comprising a single light source for governing traffic entering therein, a line circuit for each signal governed by the associated track circuit, and means effective whenever there occurs a failure of the light source of the forward signal when said forward signal is conditioned to display a permissive indication for controlling the line circuit of the rear signal to cause said rear signal to display a restrictive indication for an approaching train.

16. In combination, a first and a second section of railway track, an approach lighted signal for each section comprising a single light source for governing trafiic entering therein,.a line circuit for each signal, and means effectively energized at all times when the forward signal is not lighted but its light source is intact for controlling the line circuit of the rear signal in such manner as to cause said rear signal to display a restrictive indication for an approaching train when said means becomes deenergized due to failure of said light source.

17. In combination, a stretch of railway track divided into blocks, a signal including a single light source comprising an incandescent filament for governing the entrance of traffic into each block, a polarized circuit associated with each signal for governing the indication provided by the signal, a checking relay for each signal for selectively governing the polarity of said po-.

larized circuit, and a line circuit for each checking relay including the filament of the signal next in advance and effective for energizing said checking relay provided the associated block is unoccupied and the associated filament is intact.

18. In combination with a section of railway track, a signal for governing the entrance of traffic into said section, means governed by traffic conditions for passing energizing current through said signal, means including a line circuit for at times passing a checking current of substantially lower magnitude than said energizing current through said signal, and means eifective upon the interruption of the flow of said checking current in said line circuit for controlling the traffic approaching said section.

19. In combination with a section of railway track, a signal'for governing the entrance of traflic into said section, a line circuit normally governed by trafiic conditions in advance for controlling the indication provided by said sig 'nal, means for at times passing a checking current of insufficient magnitude to provide an indication through said signal, and means effective upon the interruption of the flow of said checking current for controlling said line circuit to thereby cause said signal to provide a restrictive indication for traffic approaching said section irrespective of trafiic conditions in advance thereof.

20. In combination with a section of railway track, a signal including an incandescent lamp for governing the entrance of tralfic into said section, means governed by trafiic conditions in advance of said section for controlling said signal, means for at times passing a checking current through said lamp of insufiicient value to cause illumination thereof, a relay operated by said checking current, and a line circuit converse position respectively, an auxiliary relay for each signal controlled over a circuit which includes the filament of the lamp of the associated signal as well as said normal or said reverse contact of the mechanism depending upon the position thereof, said auxiliary relay having a slow acting interval sufficient to bridge the reversal of said mechanism, and means controlled by the auxiliary relay for reversing the polarity of the associated polarized line circuit to thereby govern traific approaching the associated signal.

22. In combination with a stretch of railway track divided into blocks, a normally deenergized light signal for each block for governing the entrance of trafiic therein, a normally energized approach lighting relay for each signal, means for deenergizing the approach lighting relay when a train enters the associated block to thereby energize the associated light signal, an auxiliary relay for each signal, a line circuit for each signal controlled by the associated auxiliary relay for governing traffic approaching the signal, and an energizing circuit for each auxiliary relay including a front contact of the associated approach lighting relay and the lamp filament of the associated signal.

23. In combination with a stretch of railway track divided into blocks, a normally deenergized light signal for each block for governing the entrance of traffic therein, a line circuit for each signal for controlling the indication provided by the associated signal, a normally energized approach lighting relay for each signal energizing the signal upon the approach of a train, 2, normally deenergized light-out relay for each sig nal, an energizin circuit for each light-out relay including a back contact of the associated approach lighting relay and the lamp: filament of the associated signal, an auxiliary relay for each signal for controlling the associated line circuit to thereby control traf'dc approaching the signal, and an energizing circuit for each auxiliary relay including a front contact of the associated approach lighting relay and the lamp filament of the associated signal.

24. In combination with a stretch of railway track divided into blocks, a signal for each block for governing the entrance of traffic therein, a line circuit for each signal for controlling the indication provided by the associated signal, a first circuit for each signal for checking the integrity thereof and effective when the signal is energized, a first checking relay for each signal included in said first checking circuit, a second circuit for each signal for checking the integrity thereof and eifective when the signal is deenergized, a second checking relay for each signal included in said second checking circuit, a pickup circuit for each second checking relay including a contact of the associated first checking relay, and means governed by the second checking relay for controlling the associated line circuit to thereby control traflio approaching the associated signal.

25. In combination with a section of railway track, a normally deenergized light signal for governing the entrance of trafiic into said section, a line circuit for controlling the indication provided by said signal, a normally energized approach lighting relay, a lighting circuit for said signal including a back contact of said approach lighting relay, a normally energized checking relay for said signal, an energizing circuit for said checking relay including a front contact or the approach lighting relay and the lamp filament of the signal next in advance, and means governed by said checking relay for controlling said line circuit to thereby providing a restrictive indication for traflic approaching said signal upon iailure of the lamp filament of said advance signal.

26. In combination with a section of railway track, a normally deenergized light signal for governing the entrance of traflic into said section, a line circuit for controlling the indication provided by said signal, a normally energized approach lighting relay for said signal, a normally deenergized light-out relay for said signal, an energizing circuit for said light-out relay including a back contact of said approach lighting relay, a lighting circuit for said signal including said back contact and the winding of said light-out relay, a normally energized checking relay for said signal, a pick-up circuit for said checking relay including a front contact of the light-out relay for the signal next in advance, a holding circuit for said checking relay including a front contact of the approach lighting relay and the lamp filament of the signal next in advance, and means governed by said checking relay for controlling said line circuit to thereby provide a restrictive indication for traffic approaching said signal upon failure of the lamp filament of said advance signal.

27. In combination with a section of railway track, a normally deenergized light signal for governing the entrance of traffic into said section, a normally energized approach lighting relay, a lighting circuit for said signal including a back contact of said approach lighting relay, a normally energized checking relay for said signal,

an energizing circuit for said checking relay including a front contact of said approach lighting relay and the lamp filament of said signal and a line circuit controlled by said checking relay for governing trafl'lc approaching said signal.

HENRY S. YOUNG.

CERTIFICATE OF CORRECTION. Patent No. 2,206,555. July 2, 191m.

. HENRY s. YOUNG.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 10, second column, lines 28 and 29 claim 9, strike out the words and comma "a track circuit for said second section," and insert the same after "track," in line 50, same claim; page ll, firstcolumn, lines8and 9, claim 15, for "the lamp filament of said unlighted signal" read --said unlighted lamp filament of the signal--.-; and that the said Letters Patent should be read with this correction therein that the same may conform to'the record of'the case in the Patent Office.

Signed and sealed this 5rd day of September, A. D. 1914.0.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents. 

